The present invention relates to some improvements made in connecting devices for catheters, perfusion equipment and systems for perfusing liquids to the human body or for draining them from it.
CH 674944 discloses a device for the connection of conduits for medical liquids to the body of a patient comprising two parts with connectors to be engaged together both having internal protrusions in form of tubes for the conduction of the perfusion liquid, which are engageable together upon the assembly of both parts of the device.
The object of the present invention, in particular, is to avoid contamination by direct and indirect contact between the elements of the connection and similarly to avoid contamination by aspiration of air or liquids from the exterior, which constitutes a problem in currently known connecting devices.
A further object of the present invention is to obtain a connection for catheters, perfusion equipment and the like for perfusing liquids to patients which is of a universal type and is applicable to normal catheters, thicker catheters for haemodialysis, urethral probes and the like.
In general, an object of the present invention is to enable the connection to be used in any type of catheter or the like.
To achieve the aforementioned objects, the connection forming the subject of the present invention is characterised in that it comprises two hollow, preferably cylindrical, external enveloping bodies which are coupled so as to slide one within the other, the bodies being open at the connected ends and having tubes for connection to the catheter or to the perfusion container respectively at the other ends. It can also be used with currently known catheters with appropriate connections at the ends. One characteristic of the present invention is that the couplable or plug-in tubes forming the body of the connection have respective internal elements which can be connected by the introduction of said external bodies one within the other, allowing the inlet from the perfusion liquid-carrying container to be connected to the outlet connected to the catheter.
For the objects of the present invention it is important that the radial distance between the external body and the internal body is considerable to prevent capillary action phenomena and, in general, that there is a path which is as long as possible between the point of union between the external bodies and the point of contact, in other words of union of the internal bodies with the result that the route of possible contamination is as long as possible, thus making it difficult for contamination to arrive at the internal connection. At the appropriate time, when the integral parts of the connection are given a considerable length, the distance between the open edges of the external body and the corresponding internal edges can simultaneously be sufficiently great to avoid manual contact during handling of the connection.
To lengthen the route of contamination, the present invention proposes the optional production of ribs or grooves in the course of said route of possible contamination, for example at the external surface of the corresponding internal element or body. It is obvious that said assemblies of ribs or grooves could also be arranged at the external surface of the internal body which remains inside the connection once the connection has been made.
The present invention will be applicable to any type of internal union of the tubes and, similarly, will be applicable to the aspiration of air and to the passage of liquids.
The new connection can be applied to the outlets of flasks, syringes, bottles or in any other suitable element.
The releasable internal connection can be produced by two tubular elements respectively fixed to each of the two external enveloping bodies which can be coupled in a sliding manner so that, when one is introduced into the other in a sliding manner, the internal tubular elements are coupled by the congruence of their ends, for example, by means of a taper of one of the tubular elements fixed in an enlargement at the other end of the other tubular element.
Said connection for the passage of liquid can similarly be formed by internal fixed tubular elements which abut in register at their ends and have elastic joints to produce the necessary seal.
It is also feasible to arrange an internal tubular element in one of the external enveloping bodies and a needle in the other, which is coupled by passing through a spongy stopper for closing the fixed extension in the other external enveloping element or by means of a cylindrical nozzle which is threaded in a preformed aperture in said spongy stopper.
A characteristic common to the various embodiments of union of the internal tubular elements is that the external enveloping bodies which are coupled to one another in a sliding manner are provided with a coupling and holding region which is effective in the position at which one of the bodies is introduced into the other, having a coupling arrangement by means of ribs interposed in one another in the axial abutment position or alternatively by means of screw-threaded end regions for coupling said bodies one another or other similar systems for instance a bayonet fitting or a closure with an external thread and the like.
Between the enveloping bodies which can be coupled in a sliding manner there is an annular chamber round the region of coupling of said external bodies which will act as a chamber for receiving any impurities in the air or liquids originating from the exterior which might normally penetrate through the coupling regions. A complementary means can consist in the arrangement of a sleeve of felt or other material, optionally impregnated with disinfectant, which is arranged in one or other of the cylindrical elements which fit together in a sliding manner to block the gap existing between them.